Adolescent "Lean PCOS" Is Characterized by Higher Insulin Resistance and Adverse Adipokine Profile

Objective: Although polycystic ovary syndrome (PCOS) is associated with high body mass index (BMI), less is known about the cardiometabolic manifestations of PCOS without excess adiposity. Among female adolescents enrolled in the Project Viva longitudinal prebirth cohort, we characterized growth, adiposity, and cardiometabolic biomarkers among those with vs without PCOS, stratified by BMI category. Methods: We defined PCOS at the mid-teen visit (mean age 17.7 years) as self-reported diagnosis or oligo-anovulation with clinical/biochemical hyperandrogenism. We obtained anthropometric and dual x-ray absorptiometry measurements. Within each BMI category (≥85th percentile vs < 85th percentile), we used unadjusted linear regression to compare growth trajectories, adiposity, and cardiometabolic biomarkers among those with vs without PCOS. We used mixed effects models to visually represent estimated BMI and linear growth trajectories. Results: Among 358 females with data at the mid-teen visit, n = 51 (14%) participants met our criteria for PCOS. Among females with BMI <85th percentile, those with PCOS (n = 27) had earlier age at peak height velocity [β = -.57 years; 95% confidence interval (CI) -0.96, -0.18], higher Homeostatic Model Assessment of Insulin Resistance (β = .77, 95% CI 0.23, 1.30), and lower adiponectin-leptin ratio (β = -.35, 95% CI -0.65, -0.06) vs without PCOS. Females with BMI ≥85th percentile had similar biomarkers by PCOS status. Adiposity measures did not differ by PCOS status within either BMI category. Conclusion: Within this population-based cohort, adolescents with PCOS and BMI <85th percentile had greater insulin resistance and adipose tissue dysfunction vs without PCOS. PCOS-associated metabolic dysfunction exist even among adolescents with BMI <85th percentile.